Angela Perelli, age 12, of San Francisco for her question:

Do ants have muscles?

Suppose a man had the same sort of muscular power as a little ant. He could invite the family into the family car and hoist the whole thing above his head. What's more, if he performed this feat in proper ant style, he would do the lifting job with his teeth, using his arms merely to guide the load into position. If ants and people were the same size, the ants would be more than 50 times stronger.

An ant has lots of muscles, and basically they work as ours do. However, from our point of view, their mighty little muscular systems are inside out. For example, our muscles are attached to the bony skeleton, which supports the body from inside. An ant has no internal bones. Her internal organs are sheathed inside a tough coat that serves as an external skeleton. Tier tiny muscles are attached to the inside of this exoskeleton.

The major muscles in our arms and legs work in pairs to bend and unbend the knees and elbows. On a miniature scale, an ant's muscles also work in pairs to move her six skinny little legs. The two major muscles that control the human elbow are long, gristly tendons, stacked with bundles of long, meaty muscle fibers. Each end of a gristly tendon is attached to a bone on the opposite sides of the elbow joint. One tendon is attached on the inside of the arm, the other on the outside, away from the body. The elbow bends when the inside muscle contracts and becomes shorter. The outer muscle relaxes and stretches around the bend.

These major muscles work together with a complex team of other muscles to move our arms and elbows. These smooth operations are stimulated by electrical signals carried by the nervous system from the brain. Pairs of tiny ant muscles work in basically the same way.

But how in the world can an ant have joints if she has no bones? The secret is in her tough exoskeleton. Most of her coat is made of crisp unbendable material, but here and there it has rings and bands of leathery material. These pliable bands are her bendable joints, and she has more than her share of them.

Each of her many leg joints is moved by a pair of tendons and muscle fibers. Their opposite ends are attached to the inside of the hard exoskeleton, on either side of the bendable joint. When one muscle contracts and shortens, the opposite one relaxes and stretches. This bends the unbendable sections of exoskeleton between one joint and the next.

As a little ant scurries about her business, dozens of muscles work at top speed to bend and unbend the joints in her busy legs. They are stimulated to contract and relax by an elaborate system of nerve fibers. These work in pairs that control the different motions of each muscle. They carry their coded electrical signals from the headquarters of the ant's nervous system, which are in her head and along her back.